Bulldozer



0a. 18, 1949. R. A. PETERSON BULLDOZER 4 Sheets-Sheet 1 Filed April 8, 1947 ooonooaooo'a JNVENTOR. foes/e r A .PETEESON &

ATTOENE).

R. A. PETERSON Oct. 18, 1949.

BULLDOZER 4 Sheets-Sheet 2 Filed April 8. 1947 INVENTOR- ATTORNEY.

Jgfl Poss/e7- A PE nsesow Oct. 18, 1949.

Filed April 8, 1947 4 Sheets-Sheet s INVENTOR. 7 .f l k P0852774. PETERSON Byfi an ATTOENEY.

' File d April B, 1947 R.IA. PETERSON 2,485,407

BULLDOZER 4 Sheets-Sheet 4 INVENTOR. E05 52 7" A Ptrsksolv .WM ha ATTORNY Patented Oct. 18, 1949 OFFICE BULLDOZER Robert A. Peterson, San Leandro, Calit. Application April 8; 1947; Serial' No. 740,048 e'olaims (crew-144i);

This invention relates to improvements in earth-'moving'impl'ements of the typeknown generally as ."bul1dozers.

A bulldozer is a blade mounted in front of a tractor; preferably of the continuous-tread type. When impel-led by the" tractor it can do many things which" call fonmoving earthysuch as levelling ground, digging'holes, building roads on the level or carving them in the sides of hills.

Up to the present, two general types of bull'- d'ozers have been developed. One: is the straight bulldozer in which the blade is mounted perpendi'cular to the path of movement of the tractor and. is used mostly for moving earth and for levelling orscra'ping. The other isthe angle bulldozer in which the blade is set at an inclined angle to the path of movement/oi the tractor and is used mostly for digging into banks of earth and for moving the earth over the low side of a cut in road building; Each of'these types of bull'- dozers is limited tocertain kinds of work; and most jobs" call for the use. at some. time of both types: This has meant thateith'er an extra blade" must be carried along in a truck to replace the other'type ofblade; ora form ofmounting' must be provided so that the blade can. be swung to either side from its straight position and used' for both purposes; Carrying" an extra blade means transportation problems and operator's time changing'from one to the other. blade mounted to function in one position as a straight bulldozerand in an inclined position as an angledozer leads'to" an inefiicient operation.

An angle bulldozer cannot become an efiicient st'rai'gl'it bulldozer merely by having its blade placed straight. In the first place; the blade of an angle bulldozer must be longer than that of a straight bulldozer because it should extend at an angle for the full width" of the tractor. If suchalong blade is moved into a straight-across position it is' much toowide for the" tractor to push when digging. A corollary is that if a straight bulldozer of proper width were set at an Using a single angle to use it as an angle bulldozer, the earth will bespille'din the path of the tractortrack or wheels because as an angle bulldozer the blade is too short. Another fault of' the conventional adjustable angle bulldozer arises from the fact that the digging corner of the blade is so farout in front of the tractor itself that l5.to,20 percent of the power is lost. Also, the bladenmstbesuspended" from a supporting frame light enough notto be too great a weight ordrag" on the front of the tractor: If it is made light it will. not be sturdyenough to stand the maximum power the of the blade.

with any fla-Iigae to-- hold the dirt in.

tractor iscapable'of: exerting at the cutting edge. Thus-efilciency has had to" be sacrificed with all the prior art devices and a makeshift operation hasv resulted.

One important object of the present invention is to. provide a newlind' of" bulldozer whichcan operate at full efficiency" in performing all the principal functions of the straight and the angle t'ypebulldozer, and which, in addition, can perform new functions not achieved" heretoforer' Another important problem related to" the use oi'fieartl r-mov-ihgmachines and solved by this invention is that heretoforethe power of the tractor has been sufli'cient to carry far-more earth than the bulldozerbl'ade could keepinfront of it. An ordinary-bulldozer bladepossessesa small earthcarrying capacity, and after this capacity is reached, theearth is-l'ost around the edges of the blade. Vertical end plates to retain the earth are not satisfactory except in about ten percent of the cases, and the usual experience is that the operator soon cuts them off and abandons them. An anglebulldbzer'has even less carryingcapacity because the earth sl'oughs off" the trailing corner Due to the fact that the blade in previous angle bulldozers had to be made sothat either edge could be used for excavation by changing the position of theblade, it was not possibleheretofore to provide an angle bulldozer The low capacity of th' priorart bulldozer blade required many additional trips tocarry' a load of dirt as compared with the number of trips necessary to carry the same. load with my improved device. Therefore an important object of my invention is to get increased carrying capacity into a bulldozer so that earth which has been cut from a bank or scraped up from asurf-ace can be carried any desired distance without losing it out of the bowl; and sethatit'can be -dumped over a bank without losing it out the bowl as the tractor is swungtotheside';

Another important object of this invention is to provide a bulldozer which without any changes or adjustments can dig from either edge or can scrape or level, functions which heretofore have been accomplished only with partial efficiency and then onlyby' changes and adjustments which usuallyhaverequiredtwo men to stop what they were doing and spend time changing blades or adjusting the blade; Thus by' my invention I providea: bulldozer which combines" in one blade ready for instant use as an angled-czar blade sect'ionto'cutin'tea right are; left bank and. having a verticai blade" at the outer edge of each v.35 angle blade section for making a simultaneous, substantially vertical cut in the bank.

Another important object of my invention is to provide a bulldozer in which the center setback portion of the blade can be lowered into cutting position where a powerful scraping or digging action is required in front of the tractor. With present-day bulldozers it is impossible to scrape generally horizontally with a short central portion of the blade. Either the whole blade must be used or one or the other corners may be lowered to dig. By my invention I provide a bulldozer in which the effective cutting width of the blade can be reduced without substituting another shorter blade or in any way reducing the carrying capacity of the implement.

Another object of my invention is to improve the levelling characteristics of a bulldozer by providing side blade sections extending at an angle to the central generally transverse blade section so that when pushing earth along a surface having transverse gullies the angularly extending side sections will support the whole blade and prevent it from dropping into the gullies as the earth fills them in.

Other objects of my invention are to provide a bulldozer with a blade which can be tipped forward and back, tilted from side to side, and raised or lowered at its corners; to provide a bulldozer in which the power is always near the blade and is applied directly to the portion which is cutting or scraping; and to provide a more generally efficient and versatile bulldozer.

Other objects and advantages of this invention will become apparent from the following description, which is given in accordance with U. S. Revised Statutes, section 4888 as a detailed description of a specific embodiment of the invention, but which is not intended to limit the scope of the appended claims.

In the drawings:

Fig. 1 is a plan view of a bulldozer embodying my invention, the tractor being only generally indicated, since any appropriate type of tractor may be used;

Fig. 2 is a side view in elevation of the bulldozer shown in Fig. 1;

Fig. 3 is a view in front elevation of the same;

Fig. 4 is a view in perspective of the improved device attached to one form of mounting means;

Fig. 5 is a side view in elevation similar to Fig. 2, showing the blade tilted back so that the center portion alone is used to dig or to scrape;

Fig. 6 is a front view similar to Fig. 3, showing the blade tilted back to the digging position shown in Fig. 5;

Fig. '7 is a front View similar to Fig. 3 except that the blade is tilted sideways;

Fig. 8 is a side View of the blade and its mounting means when in the position shown in Fig. 7; and

Fig. 9 is a plan view of an alternative form of arcuate blade.

(see Fig. 2), an upwardly and forwardly extending cutting blade section 40 mounted adjacent the outer end of each of said angular blade sections 34 (see Fig. 4), arms I4, I5, I8, etc. for mounting said implement on said vehicle, and lifting means I I for raising and lowering said implement. The arms I8 may be shortened to tilt the cutting blade about an axis generally parallel with the driving axle of the tractor I0 so that the central section 33 of the cutting blade is lowered in relation to the outer extremities of the side cutting sections 34 (see Figs. 5 and 6).

Referring more specifically to the illustrative device in the drawings, the tractor I0 is a conventional, continuous track type of tractor, such as provides the impelling means for any of the bulldozers now in use. A pulley system II is mounted on the front of the tractor I0 and supports the block I2 which is pivotally fixed to the bulldozer frame member I3. The rigid support arms I4 and I5 are each fastened to the driving frame of the tractor II] by a ball and socket joint I6 which permits movement up and down and also permits a limited relative sidewise movement when in the position shown in Fig. 8. The opposite end of each of the arms I4 and I5 is connected to the bulldozer frame at the joint I1. The bulldozer is supported and adjusted relative to the arms I4 and I5 by the spacer members 18, which are rotatable and engage the exteriorly threaded rods I9 with their interior threads 20. The upper threaded rods I9 are connected with ball-and-socket type joints 2| near the top corners of the bulldozer side frame members 22 and the lower threaded rods I9 are pivoted at 24 to a bracket 25 secured on each of the arms I4 and I5. Cross braces 23 hold the bulldozer frame in lateral alignment with the tractor. These braces are pivoted at 21 to the arms I4 and I5 and have ball and socket joints 28 where they connect to the bulldozer frame cross member I3.

The bulldozer frame should be sufficiently strong to support the cutting blade properly at all points. The one illustrated here is composed of the lower horizontal cross-member I3, a similar upper member 30, vertical corner posts 3I, and side frame members 22 and 23 which are tied together at the front by the heavy vertical cutting plate 32. There may be as many additional supporting braces as a designer may choose but those shown here have proven adequate in use.

The bulldozer blade consists preferably of three blade portions: a center set back portion 33, and two sloping side portions 34 and 34, which extend at an angle out from and forward of the center portion 33. Concave body portions 36, 31, and 38 extend upwardly from these blade portions. Although any dimensions may be used, I have found that a very efiicient blade is made by having each of these three cutting blade portions about four feet long and the concave portion about three feet high. A good angle for the forwardly extending side blade sections 34 in relation to the central blade section 33 is about 30 degrees, as shown in Fig. 1. When viewed as in Figs. 2, 3 or '7 all of the cutting blade edges 33 and 34 lie in substantially the same plane. Mounted adjacent the outer end of each of the side sections 34 is the forwardly and upwardly extending cutting plate 32, having a cutting edge 40 which can be used for cutting vertically into the sides of hills.

Another form of blade which can accomplish many of the features of this invention is one essentially like the above where each section 36, 31, and 38 is curved instead of being straight.

SeelFig. 9. :Such :a flolade :gooii :digging and earthacarrying acharacteristicsaand :is intended to come within the :scope cof the v:cl'aims :appended hereto. zExceptlfortthes-fact that more Welding would rbe involved the sections 333.231.1(1 :34 could be divided iup iinto :m'ore ssections .and :still accomplish the :results :df :my invention. An impoittantifeature of sthis imention is ithe :fact that the cutting blade slopes inwardly at eachvouter edge zandthat these inwardlyisloping: sections are joined [by ra straight aor :gently :curved central .set bacmbladeeection.

Bhe lblade :as rshowna in lth'e drawings includes two'angularly set "sections 34 which are set to out iin ithe :marmer 11f .angledozer. If the two blades i3! and 33 cameitogether 'atzan angleilike a '*V,:many of ithe :objections :already noted :about angle' bull'dozers*would apply, with the additional objection that not =very 'much of a bowl would be formed forccarrying dirt. 'Theset back center portion-3B extending partway across the front of the tractor =i0.'gives-'depth to the dirt-carrying bowl and also renders it possible to place the cutting blades very close to the tractor, so that the power is "appliedto the ends of the blades 36 and 3 througharms H4 and i5 which are practically *no longer than those in use on ordinary-straight bulldozers *and can be just as sturdy. ln-other words, the cutting is done by a-bla'dewhich is'close in to the tractor, is'ready to 'use"foranjgle=dozing or straight cutting; and is not -one pivoted as in the prior art at the end of a frame setfar enough out in front of the tractor'sothatthereisclearance for the operator to tilt it to either side whenusing it'as an angledozer'for'digging'onoppositebanks.

Among other .things, .what .my .invention has done is to put carrying capacity into a bulldozer plus providing an angledozer on either side ready for immediate use without any adjustment by the operator.

Figs. 5 and '6 illustrate'how with my device it is possible to cut down the-digging width to substantially that of the middle blade section '33 plus a small bit of the 'angularl-y set adjacent blade sections 3 4. This a isdone by shortening the arms I8 which tilt the implement about an axis generally parallel with the driving axle of the tractor 10. In other words, it raises the outer ends of the blade sections 34 in relation to the blade section 33. In Figs. 5 and 6 the blade is in this tilted position ready to be pushed forward by the tractor. The depth of out can be regulated by the cable ll. As the tractor moves forward the dirt will roll up in front of the concave section 36 and spread sidewise into the sections 31 and 38. The digging will be confined mostly to the earth below the blade section 33.

Fig. 2 illustrates another advantage of this construction where the forwardly extending side blade sections 34 serve as runners or supports for the center blade section 33 and prevent the blade from dropping into transverse ruts 4| in the road. The result is that the earth in the bowl will fall into these ruts and soon the surface will be smooth and packed.

The adjustment shown in Figs. '7 and 8 is useful where a road is being cut in a side hill and the blade should be set at an angle relative to the transverse axis of the tractor II). By raising the blade vertically (by means of the pulley II) and by shortening one of the adjusting members 18 relatively to the other, the natural adjustment of equilibrium will tilt the blade to one side as shown in Figs. '7 and 8. There the blade :portion :M as (considerably Ilower i'than the blade rp'ortion 138, :and the 'sentire l-blade amay ibe as ihigh above the ground :as is .fl'esired, limited only by the Iheightt rof ithe pulley:system H.

The great versatility :of the :invention :renders it capable of :use in many ways 'in :construction work which 'iheretofore have either been :impossible for Ehave required several idifierent itypes of machines.

1. An earth cutting and moving implement adaptedzto bemmunted onxand'propelledzinefront of re. power-:driven lvehicle, :comprisinga cutting bladezlyingssubstantiallyinpne'plane:andibeingof generally-aarcuate shape =when1viewe'drin'plan with the outer:sideportionsrofthe blade pointingiahea'd cf ther-central :portion of the bla'de as mounted on said vehicle; aside arms secured ito said vehicle along :its sidet-and :extending ;forward itransverse pivotal connecting :means :securing said cutting blade to the :forward iends :of :said side arms; support .arms transversely :pivoted' tozsaid cutting blade at :points spaced :apart from where said side arms are connected tosaid blade,:. and zpivoteri to the 'r forward lends Lof ?said .side arms .aft lOf where the blade'isconnected thereto; andsmeans for changing the length :ofzsaid support arms relation to i that iportion *of :said side arms which lies ibetween their forward ends and where :said support arms :are secured ito it; 'whereby 'said arcuatecutting blade may be rotated about .said transverse pivotal iconnectingimeans .to bring the central portion=ofzsaid rblade'lintota'lower cutting position .than .its router rside -portions :thereby reducing the effective cutting widthlof *said .blade.

2. An earth cutting :and moving implement adapted to be mountediomand propellediin .front of -a power-driven ve'hicle,:comprising .a cutting blade lying substantially .in 'one plane andibeing of generally arcuate shape when viewe'd .inrplan withthe outer 'side portions-o'f the bla'de pointin'g ahead *of the central portion of the blade as mounted-on'sa'id vehicle :and having an upwardly and forwardly extending cutting blade section mounted adjacent the outer end of each of said outersideportions of=the blade =s'ide' armssecured to said vehicle along its side and extending forward; transverse pivotal connecting means securing said cutting blade to the forward ends of said side arms; support arms transversely pivoted to said cutting blade at points spaced apart from where said side arms are connected to said blade, and pivoted adjacent said side arms aft of where the blade is connected thereto; and means for changing the length of said support arms in relation to that portion of said side arms which lies between their forward ends and where said support arms terminate; whereby said arcuate cutting blade may be rotated about said transverse pivotal connecting means to bring the central portion of said blade into a lower cutting position than its outer side portions.

3. An earth-moving implement adapted to be mounted on and propelled in front of a powerdriven vehicle, comprising a cutting and carrying blade having a central cutting section extending partway across the front of said vehicle, and a side cutting section for each side with the cutting edge lying in substantially the same plane as the cutting edge of the central section, each side section being connected to said central section at its inner end and extending forwardly and outwardly from said central section to provide at each side of said implement a cutting edge generally angular in relation to the fore and aft axis of said vehicle; arms for mounting said implement on said vehicle; transverse pivotal connections between said arms and said blade; and bracing means for supporting said blade in fixed relation with respect to said arms; said bracing means including means for adjusting said blade about an axis generally parallel with the driving axle of said vehicle whereby the central cutting section of said cutting blade may be lowered or raised in relation to the outer extremities of said side cutting sections.

4. A materials moving implement adapted to be mounted on a power-driven vehicle and propelled by the same, comprising a cutting, pushing and carrying blade having a central section extending part-way across said vehicle, and a side section for each side with the cutting edges lying in substantially the same plane as the cutting edge of the central section, each side section being connected to said central section at its inner end and extending forwardly and outwardly from said central section to provide at each side' of said implement a cutting edge generally angular in relation to the fore and aft axis of said vehicle; means for mounting said implement on said vehicle; transverse pivotal connections between said means and said blade; and bracing means for supporting said blade in predetermined relation with respect to said mounting means; said bracing means including means for adjusting said blade about an axis generally parallel with the driving axle of said vehicle whereby the central cutting section of said blade may be lowered or raised in relation to the outer extremities of said side cutting sections.

5. A materials moving implement adapted to be mounted on a power-driven vehicle and propelled by the same, comprising a cutting blade lying substantially in one plane and being of generally arcuate shape when viewed in plan with the outer side portions of the blade pointing ahead of the central portion of the blade as mounted on said vehicle; side arms secured to said vehicle along its side; transverse pivotal connecting means securing said cutting blade to the ends of said side arms; bracing means transversely pivoted to said cutting blade at points spaced apart from where said side arms are connected to said blade, and pivoted to said side arms to form a brace; and means for changing the length of said bracing means whereby said arcuate cutting blade may be rotated about said transverse pivotal connecting means to bring the central portion of said blade into a lower or higher cutting position than its outer side portions.

6. An earth cutting and moving implement adapted to be mounted on and propelled in front of a power-driven vehicle, comprising a cutting blade lying substantially in one plane and being of generally arcuate shape when viewed in plan with the outer side portions of the blade pointing ahead of the central portion of the blade as mounted on said vehicle; a side arm secured to said vehicle along each side; transverse pivotal connecting means securing said cutting blade to the ends of said side arms; a bracing means on each side of said vehicle transversely pivoted to said cutting blade at points spaced vertically apart from where said side arms are connected to said blade for supporting said blade in predetermined relation with respect to said arms; and means for changing the length of one or both of said bracing means in relation to the length of said side arms; whereby said arcuate cutting blade may be rotated about said transverse pivotal connecting means as well as about an axis extending on the fore and aft line of said vehicle to bring the central portion of said blade into a lower or higher cutting position than its outer side portions or to lower one corner into a lower cutting position than the other corner.

ROBERT A. PETERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,989,431 Stamm Jan. 29, 1935 2,230,704 Sorensen Feb. 4, 1941 2,408,268 Peterson Sept. 24, 1946 

